Liquid pressure remote control system



Sept. 17, 1940. 1UP BEESTON 2,215,169?

LIQUID PRESSURE REMOTE CONTROL SYSTEM Filed -May 24.l 1958 3 sheets-sheet 1 30 of the Venturi-shaped passages.

Patented Sept. "17, 1940 I t UNITED STATES PATENT OFFICE LIQUID PhRESSURE REMOTE CONTROL SYSTEM `John Percival Beeston, London, England, assignor to Automotive Products Company Limited, London, England Application May 24, 1938, Serial No; 209,734 In Great Britain May 26, 1937 6 Claims. (Cl. 60-97) This invention relates to liquid pressure rethe other pair of Venturi-shaped passages so as to mote control systems in which the flow of liquid be actuated by fluctuations in the flow of liquid from a common source is required to be divided through said other pair of passages. This arequally or in a predetermined ratio so as to rangement enables the equalising eiect to be obpass from a plurality of separate passages for tained during operation of the'jacks or the like 5 feeding corresponding pieces of apparatus and in both directions.

causing them to be actuated tozequal extents The invention is illustrated in the accompanydespite variations or inequalities in the resistance ing drawings in which to iiow offered by said apparatus. Figure 1 is a sectional diagram to show the l0 It is the primary object of the present inven-A connections between the parts in one form of 10 tion to provide :.a improved form of equalizing hydraulic remote control system embodying an valve device which is intended more particularly equalising valve;

for use where a plurality of hydraulic jacks or Figures 2 to 5 are sectional views of oneconequivalent are required to be actuated in unison struction of valve arranged as in Figure 1, Figure from a common source of pressure liquid. 2 being a sectional plan on the line 2--2 of Figure l5 In a liquid pressure remote control system hav- 3, Figures 3 'and 4 being sectional elevations on ing a plurality of jacks which are required to the lines l3---3 and 4-4 respectively of Figure 2, work in unison from a common source of pressure and Figure 5 being an end sectional elevation l liquid, the present invention is characterised by taken'on the line 5--5 of Figure 4;

the provision of a ow equalising device com- Figure 6 is a sectional plan of a simplified 20 prisng a plurality of Venturi-shaped passages form of equalising valve device; and through which the liquid streams corresponding Fig-ure 7 is a sectional elevation of the valve to the respective jacks are caused to pass, and a device taken on the line 'I-l of Figure 6. Valve device which is actuated by pressure The remote control system depicted as an eX- changes caused by the Venturi-shaped passages ample in Figure 1 comprises a pump Ill which is 25 so as to control the distribution of pressure liquid conveniently motor driven, such as by the engine to the respective jacks, said Valve device conof an aircraft, and is adapted to feed liquid under veniently being actuated by iiuid pressure means pressure to a selector valve II of the usual conoperatively connected with the throat portions struction, said valve being adapted to return the liquid to the inlet of the pump I Il through a pipe There is also provided according to the in- I2, or to conduct it to either one of a pair of vention a liquid pressure remote control system `pipe lines I3 and I4, both of these being concomprising a pair of double-acting jacks which nected with an equalising valve device according are required to work in unison from a common to the invention and indicated generally at I5. A

source of pressure liquid, a Venturi-shaped paspair of double-acting jaclrs orthe like shown dia- 35 l sage inserted in the pressure pipe line leading grammatically at I6 and I'I respectively are conto each jack, and a valve device which is operated nected by pipe lines I3, I9, and 20, 2l with the by the liquid pressure fluctuations in the Venturlvalve device I5. The' arrangement is such that shaped passages and retards thev movement of when the pressure liquid from the pump I0 passes 40 one or the other jack by restricting the iiow of to the pipe line I3, the liquid stream is divided 40.y

return liquid therefrom. between the pipe lines I9 and 2l and causes both The invention also consists in an equalising of the jacksI I6 and II to be shortened simulvalve device for a liquid pressure remote control taneously, while the actuation of the selector system and comprising in combination with a pluvalve I I so as to connect the pressure liquid withvrality of Venturi-shaped passages tobeconnected the pipe line I4 similarly feeds said pressure 45 in the pipe lines of the respective jacks, a throtliquid through the pipe lines I8 and 20 so as to tling valve which is responsive to pressure iluccause both jacks I6 and I1 to extend. It will be tuations in the Venturi-shaped passages and appreciated that when pressure liquid is supplied which is also connected in said pipe lines so as to to the pipe line I4, the liquid rejected by the restrict the flow of pressure liquid therethrough jacks is returned through the pipe line I3 to the 50 for controlling the operation of the jacks. Con- )inlet connection I2 and vice versa, a reservoir 22 'veniently two pairs of Venturi-shaped passages also being connected with the inlet pipe I2 so may be provided, each pair being connected reas to keep the system filled with liquid.

spectively with a corresponding flow-controlling The pipe line I3 is connected with a passage 23 '55 valve device. which latter .1s interconnected, with in the' valve device I5, said passage 23 inter- 55 secting a valve bore 24 and being continued so as to accommodate slidably a by-pass valve piston 25 which is free to move between a shoulder 26 and a stop member 21. The bore 24 contains a slidable dumb-bell shaped valve member 28 having piston-like heads 29 and 30 whicliflt the bore 24 in a substantially fluid tight manner and which cause the valve member 28 to be responsive to any difference in the fluid pressures existing within chambers 3| and 32 at the ends of the bore 24. The bore 24 is formed with a pair of annular grooves 33 and 34 which are positioned so that when the valve member 28 is in its central position both grooves are just completely uncovered by the heads 29 and 30 of the valve member 28. Axial movement of the valve member 28 causes one or other of the grooves 33 and 34 to be partlyv closed. The annular groove 33 is connected with a passage 35 which is shaped in the manner of a Venturi water-meter and is herein referred to as a Venturi-shaped passage, the characteristic features of such passage being the provision of streamline converging and diverging parts 36 and 31 forming a throat 38 between them. Similarly the groove 34 communicates with a Venturi-shaped passage 39 having a throat portion .40, said passages 35 and.39 being connected respectively with the pipe lines 2| and I9 feeding the jacks I1 and I6. Adjacent the valve bore 24 thepassages 35 and 39 are extended laterally as indicated at 4I and 42 so as to communicate with the passage 23 when the by-pass piston member 25 is retracted, although,

of course, this connection is cut off when said member 25'is in the position shown in Figure 1.

In a similar Way thepipe line I4 is connected by way of a passage 23a and valve member 28a with a pair of Venturi-shaped passages 35a and 39a leading respectively to the pipe lines 28 and I8 of the jacks. The construction of these and the associated parts is the same as that just described, and in Figure 1 the same reference numerals are employed using in addition the suflix a.

In order to control the working of the ,valve members 25, 28, 25a and 28a the passages at the lower part of the valve device I5 in Figure 1 are interconnected with the passages in the upper part thereof as follows. From the throat- 38 of the passage 35 a connection 43 leads to the chamber 32a, and similarly a connection 44 joins the throat 40 of the Venturi-shaped passage 39 with the chamber 3| a. Also, the passage 23 'communicates with a space 45a behind the valve piston 25a by way of a connection 46. Corresponding connections 43a and 44a feed liquid to the chambers 32 and 3| from the passages 35a and 39a, while a connection 46a communicates with a space 45 and brings about the operationof the by-pass valve piston 25.

It is Well known that when a stream of liquid under pressure flows through a passageway hav- -ing a constricted throat portion, such for example as the Venturi-shaped passages 35, 39,350. and 39a in Figure l, the pressure of the liquid at the throat portion is considerably reduced owing to the high velocity of the liquid, and this effect is utilised to operate the valve members 28 and 28a. in such a manner as to equalise substantially the rate at which the pressure liquid flows through lthe pipe-lines I9 and 2| or I8 and 20 irrespective of the fact that the pressure in one ofthe pipe lines may be greater than that in the other owing to there being a greater load on one jack. Assuming that the selector valvel I I is operated to conduct the pressure liquid through the pipe line I4, it will be seen that this liquid ows'freely past the middle part of the valve member. 28a and thence is divided into two streams which ow through the Ventiuri-shaped passages 35a and 39a respectively, thus reaching the left hand sides of the jacks I1 and I6 respectively. At the same time the reduced pressure at the throat of the passage 39a is transmitted by the connection 44a -to the chamber 3| of the valvemember 28, and similarly thereduced dpressure at the throat of the passage 35a is placed in communication with the chamber 32. If, therefore, the rates at which the liquid flows through the passages 35a and 39a tend to become unequal the reductions in the pressures at the throats will vary correspondingly, and as a consequence the valve member 28 will be moved out of its central position as it will have a greater fluid pressure at one end than the other. It will be noted that the extension of the jacks I6 and I1 caused by the pressure liquid supplied through the pipe lines I8 and 20 brings about the expulsion of liquid from the jacks through pipe lines I9 and 2| ,H and that the jacks'can only be extended so long as this liquid is free to escape. It is the function of the valve 28 to regulate the rate at which the liquid can so escape through the pipelines I9 and 2|, and in this .way the action of the jacks I6 and I1 is controlled. Further, the pressure of liquid in the prevailing supply pipe line I4 is communicated by way of connection 46a' to the space 45 behind the piston valve member 25, thus causing it to isolate the passages 4| and 42 from the passage 23 and compelling the liquid from the Venturi-shaped passages 35 and 3 9 to pass into the annular grooves 33 and'34 before it can reach the prevailing return pipe line I3'. Supposing therefore that vthe jack I1 is rather stiff or has a heavier load to bear than the jack I6, there will naturally be a tendency for a greater quantity of liquid to flow through the Venturi-shaped passage 39a' than through the passage 35a. This brings about a greater,s reduction in the pressure within the chamber 3| than in the chamber 32 and consequently causes the valve member 28 to slide into a position where it partially closes the annular groove 34, thus throttling the return of the rejected liquid from the jack I6 through the pipe y line I 9. This, of course, retards the movement of the jack I6, and by suitably proportioning the parts a substantially equal rate of movement can be 'obtained with a relatively large difference in the loading of the jacks I6 and I1. Differences may perhaps exist in the rates at which return liquid ows through the Venturi-shaped passages 35 and 39 thus tending to change the position of the valve member 28a, but this will not affect the supply of pressure liquid as the by-pass .piston valve 25a is forced to its fully open position due to the superiority of the pressure liquid in the paasa'ge 23a relative to the pressure of the return liquid in the passage 23. When the jacks I6 and I1 are operated in the reverse direction by supplying pressure liquid through the pipe line I3 exactly the same result is achieved, since the by-pass valve piston 25 is then caused to open and the'valve member 28a regulates the flow of the return liquidl under the influence of the reduced pressures existing at the throats of the Venturi-shaped passages 35 and 39.

Constructional details of lan equalising valve idevice arranged substantially in accordance with )are constituted by sleeves 41 disposed in the upper part of a valve body indicated at 43, said sleeves each havinga small radial hole which extends from its throat portion and communicates with an annular chamber 49 formed by a circumferential groove in the exterior of the sleeve 41. The Venturi-shaped passages 35 and 39 are arranged similarly in the lower part of the body 48 as will be clear from Figure 3. To make the valve members 28 and 28a more sensitive and light in operation the two ends of each are provided with relatively large flat piston members 5|, which are freely slidable each within a cylinder space indicated at 52 and closed by a cover plate 53. The purpose of these piston members 5I is to enlarge the area which is subject to the reduced liquid pressure at the throat portions of the Venturi-shaped passages. and the arrangement of the connection will be clear from Figure 5. The connections 43a and 44a are drilledas shown so as to place the throat portions of the passages 35a and 39a in communication with the chambers 32 and 3| respectively and in addition chambers 3Ib and l3217 on the opposite sides of the piston members 5I are joined to the Venturi-shaped passages by connections indicated at 44h and 43h, respectively. These passages 43h and 44h do not, of course, intersect but pass one to each side oi the connection 46 as will be seen in Figure 4. The connections between the valve member 28a and the throat portions of the Venturi-shaped passages 35 and 39 are arranged similarly at the opposite end of the body 48. It will be seen that the re duced pressure existing at the throat portions of the Venturi-shaped passages when the device is in operation is transmitted to a large area on the valve members; for instance the reduced pressure at the throat portion of the Venturishaped passage 35a acts upon the whole of the outer surface 54 of the piston member 5| attached to the end part 30 of the valve member 28 and simultaneously acts upon the annular surface 55 of the piston member 5| at the opposite end of said valve member 28, thus rendering the latter very sensitive to differences in the rates of ow of the liquid through the passages 35a and 39a. The piston members 5I need lnot be aliquid tight fit within the corresponding cylinder spaces 52, as in operation there is relatively little pressure difference between the two sides of each piston member 5| when once the valve member has assumed a position of equilibrium. l f

The simplied, but less satisfactory form of equalisingvalve device shown in Figures 6 and '1, employs only one pair of Venturi-shaped passages, these being indicated at 35 and 39. Both are connected byr pipe lines I4 and |4a with a selector valve II as before, this being associated with a pump II) and reservoir 22. At their other ends the Venturi-shaped passages 35 and 39 are connected respectively with pipe lines I8 and 20 which are used to feed pressure liquid to jacks I6 and I1 in order to bring about their extending movement. As before, the liquid rejected by the jacks during this movement passes through pipe lines I9 and 2| and is fed through passages 56 and 51 respectively which terminate in annular grooves 33a and 34a formed in a valve bore 24a. A central annular groove 58 also formed in this bore communicates by a passage 59 with the pipe line I3 leading back to the selector valve II. In this example the piston valve member 28a is formed with a plurality of lenticular-shaped grooves 6I! which, when the valve member 28a is centrally disposed, connect the two passages 56 and 51 with the pipe line I3. The two ends of the bore 24a are closed by caps 6I and 62 which are tted with packing washers 63 and are adjustably held in place by set screws^64 passing through covers 65 and 66, locking nuts 61 being provided. This leaves chambers 3Ia and 32a which are connected respectively with the throat portions of the Venturi-shaped pas-,- sages 39 and 35 respectively by passages, such as those indicated at 44 in Figure '7. Y

The device operates in4 a manner similar to the previous example when the selector valve II is set so as to deliver pressure liquid through the pipe line I4 (and Ma) in order to extend the jacks I6 and I1, the flow of liquid through the Venturi-shaped passages 35 and 39 causing reductions in pressure at their throat portions depending upon the rates at which the liquid is flowing through the passages 35 and 39. If these rates are unequal the Valve member 28a is urged towards one end or the other of the bore 24a and thus has the effect of throttling the return of liquid from the jack which tends to move fasterl than the other. The equalising valve 'is found to be most eiective when the system is working under load as this enables a relatively large reduction in pressure to be produced in the Venturi-shaped passages. If desired, a constriction indicated at 68 may be introduced into the return pipe line to raise the pressure in the system. When the selector valve II is operated to shorten the jacks by delivering pressure liquid through the pipe line I3, the valve member 28a is actuated by any difference in the flow of the rejected liquid through the Venturi-Shaped passages 35 and 39 and has the effect of throttling the pressure liquid which is being delivered to the jacks through the passages 56 and 51. It is found, however, that the valve device is relatively insensitive when the jacks are operated in this direction. f

In all cases it is desirable that the Valve which elects the throttling and regulates the distribution` of liquid through the jacks or equivalent units shall be incapable of completely shutting ofi` either system. It will be appreciated moreover that Venturi-shaped passages may be employed in ways other than those described in order to control a valve automatically for the purpose of ,regulating the distribution of liquid through a plurality of systems fed from a common source. By the term Venturi-shaped passage'fis of course meant a passage which diminishes in cross-section to form a throat portion and then is enlarged again in a substantially stream-line form so as to incur only a relatively small frictional loss, and in which a connection is taken from the passage adjacent the throat thereof for the purpose of controlling a valve device responsive to the reduced pressure at the throat. In some cases, such for instance as where units of different sizes are to be operated in unison, theflow equalisingvalve may be arranged to distribute the pressure liquid so that the rates of ow inthe respective branches are, not equal but bear a predetermined constant ratio one to. another, suitable for bringing abou the operation of the units in unison. ,The improved equalising valve and remote control system utilising the principle of the Venturi passage may be employed in many ways other asv than that described, and, if desired, provision can be made for equalising the flow in more than two separate circuits, as for instance by having a Venturi passage in each circuit and an individual valve me'mber for each pair of circuits. Moreover, it will be appreciated that the use of Venturi passages as the actuating means for the regulating device enables a considerable pressure drop to be obtained without having to accommodate an equal pressure drop in the delivery. This enables the equalising valve to be placed in a high pressure portion of the system, and at the same time work in a sensitivemanner on account of the relatively great pressure drop which the Venturi passage is capable of producing. The improved equalising valve described may, ofV course, be used .for applications apart from hydraulic remote control systems.

What I claim is:

1. A double-acting remote control system comprising a reservoir, a source of pressure liquid, a selector valve fed with pressure liquid from said source andconnected with said reservoir, a pair of main pipe lines connected with said selector valve, said valve selectively feeding one of said main pipe lines' with pressure liquid and connecting the other of said main pipe lines to said reservoir, a distributing valve in each main pipe line, double-acting jacks, branch pipe lines between each distributing valve and corresponding ends ofmsaid jacks, the said distributing valve acting to restrict variably the liquid ilow through one or other of the branch pipe lines, a Venturishaped passage including a throat portion provided in each of said branch pipe lines; means for actuating each distributing valve by Huid pressure, and connections from said actuating means of each distributing valve to said throat portions associated with the other distributing valve.

2. A double-acting remote control system comprising a reservoir, a source of pressure liquid, a selector valve fed with pressure liquid from said source and connected with,said reservoir, a pair of main pipe lines connected with said selector valve, said valve selectively feeding one of said main pipe lines with pressure liquid and connecting the' other of said main pipe lines to said reservoir, a distributing valve in each of said main pipe lines, a pair of double-acting jacks, a pair of branch pipe lines from each distributing valve leading to corresponding ends of said jacksmthe said distributing valve acting to restrict variably the liquid iiow through one or other of the branch pipe lines, a Venturi-shaped passage having a throat lportion provided in each branch pipe line,` means for actuating each distributing valve by uid pressure, connections from said actuating means of each of said distributing valves to the throat portions of the Venturi-shaped passages joined with the other distributing valve, and a bypass valve device for each of said distributing valves arranged when open to bypass its distributing valve, each by-pass valve being arranged to be opened by the uid pressure in its own mainv pipe line and to be closed by the uid pressure in the other main pipe line whereby -the distributing valve in the pipe line whichfeeds pressure liquid is rendered inoperative while the distributing valve in .the other main pipe line carrying the return liquid to said reservoir is rendered operative.

3. A remote control system according to claim 1, in which each distributing valve comprises a body, a bore in the body Vclosed at both ends, a

plunger slidable axially inthe bore and having -a head at each end fitting in said bore', a connection to one of said main pipe lines at the middle part of said bore, a pair ofpassages con- 'nected respectively with said branch pipe lines in which each distributing valve comprises a body,

a bore in said body and having a central portion and enlarged chambers at its nds, a piston axially slidable in'said bore for restricting one or the other of said branch pipe lines, said piston being provided with an enlarged head at each end thereof, each head being slidable respectively in said chambers, dividing the latter into two compartments, inner and outer, respectively, and connections joining each outer compartment with the inner compartment at theopposite end of said bore so that each of said valves is rendered sensitive to variations in the Aratio of the pressures at said throat portions of the Venturi-shaped passages by which each valve is actuated.

5. A remote control system according to claim 2, in which each by-pass valve comprises a bore, a plunger member slidable in said .bore so as to provide at one end thereof a iiuid space connected with said main pipe line of said other distributing valve, the other end of said member closing off adjacent Venturi-shaped passages from direct connection with the other main pipe line.

6. In a remote control system including a source of pressure liquid, a reservoir,P and a pair of double-acting jacks: a iow equalizing valve device-for securing -simultaneous and equal operation of said jacks when fed from said source, a

`pair of main pipe lines connecting said device with said source and with said reservoir respectively, and two pairs of branch pipe lines connecting said device with said jacks, said equalizing valve device comprising a body, a pair of distributf ing valve connected respectively with the main 'pipe lines, two pairs of Venturi-shaped .passages `including throat portions formed in said body,

each pairA being connected at one end with the corresponding distributing valve and at the other end with the branch pipe lines leading to corre? spodng ends of said jacks, whereby each distributing valve is arranged to-restrict variably the ow of liquid through one or other of the pair of Venturi-shaped passages with which it is connected, and two uid pressure means for operating the distributing valves respectively, each of said fluid pressure means being connected with the throat portions of that pair of Venturi-shaped passages associated with the other distributing valve so asto be operated by variations in the dilferential pressure between said two throat portions.

JOHN rERCIvAL 'BEESTON 7o 

